1. Field of the Invention
Aspects of the present invention relate to a developing cartridge and an image forming apparatus having the same, and more particularly, to a developing cartridge and an image forming apparatus having an improved configuration of a developer regulating member.
2. Description of the Related Art
In general, image forming apparatuses are connected to a host apparatus and print images of data stored in the host apparatus on a printable medium (such as printing paper, transparencies, and the like) according to an output signal from the host apparatus. One of such image forming apparatuses is an electrophotography type, which is provided with a photosensitive body on which an electrostatic latent image is formed, a developing unit to develop a developer on the photosensitive body, and a transferring unit to transfer the developed developer on the photosensitive body to the printable medium. The electrophotographic image forming apparatus may be a printer, a photocopier, and/or a multi-functional device.
FIG. 1 is a schematic view illustrating a configuration of a related art electrophotographic image forming apparatus 100. As shown in FIG. 1, the electrophotographic image forming apparatus 100 comprises a feeding part 110 to store printable media, an image forming part 140 to form an image on the printable media supplied from the feeding part 110, a fixing part 150 to fix a developer on a surface of the printable media by heat and pressure, and a discharging part 160 to discharge the printable media on which an image is formed.
The image forming part 140 comprises a light scanning unit 130 which receives image information of an image data from a light signal to form an electrostatic latent image on the surface of a photosensitive body 122, and a developing cartridge 120 which spreads developer on the electrostatic latent image on the photosensitive body 122 formed by the light scanning unit 130, and which transfers the developer to contact the printable media to form the image on the printable media.
The developing cartridge 120 is detachably provided in a main body 170 of the image forming apparatus 100. Accordingly, the developing cartridge 120 is a consumption good capable of being replaced when the developer stored therein runs out. The developing cartridge 120 comprises an electrifying roller 121 to electrify the photosensitive body 122 to a predetermined potential, the photosensitive body 122 to form an electrostatic latent image on the surface thereof by the exposure of the light scanning unit 130 after being electrified to the predetermined potential through the electrifying roller 121, a developing roller 123 to spread the developer on the electrostatic latent image formed on the surface of the photosensitive body 122 that contacts the photosensitive body 122, a supplying roller 124 to supply the developer to the developing roller 123, a developer regulating member 125 to regulate the amount of the developer supplied to the developing roller 123, and a developer storing part 126 to store the developer.
In the related art developing cartridge 120 with the above described configuration, the developer regulating member 125 is able to maintain a regular (or consistent) thickness of a developer layer while the developing roller 123 rotates and the developer is supplied from the supplying roller 124. The developing roller 123 contacts and rotates in the same direction with the photosensitive body 122 to maintain a regular distance therebetween. Then, the developer on the surface of the developing roller 123 is attached to the electrostatic latent image of the photosensitive body 122 by a potential difference between the photosensitive body 122 and the developing roller 123. Accordingly, a visible image is formed on the photosensitive body 122.
Then, the developer on the photosensitive body 122 is transferred to the printable medium by a transferring roller 141 to form an image on the printable medium.
Here, the developer regulating member 125 regulates the density of the developer transferred from the developing roller 123 to the photosensitive body 122 according to the length (a free length) of the developer regulating member 125 from a casing 128 to a free end part that contacts with the developing roller 123.
However, such a related art developer regulating member 125 is fixedly coupled to the casing 128 and has the same free length regardless of the different product models of the electrophotographic image forming apparatus. Accordingly, it is difficult to keep the density of the developer output on the printable medium uniform because a tangential pressure applied to the developer is non-uniform as the developer regulating member 125 is made of material having non-uniform characteristics.
Also, when a user is not satisfied with the developer density, there is no way to physically regulate a position of the developer regulating member 125 to adjust the density of the developer. Accordingly, a user is inconvenienced by having to regulate the density of the developer only by selecting the density through an image forming apparatus driver.